A gas transfer processing method, such as a gas absorption method or a gas release method, for transferring gas in and out of a liquid is known as a component transfer processing method for transferring a target component to an absorption liquid. The gas absorption method is designed for absorbing gas into a liquid, while the gas release method is designed for releasing gas from a liquid. In recent years, to achieve such a gas absorption or gas release process by means of compact equipment, for example, there is known a technique in which a liquid is allowed to flow through fine flow paths formed in a microchannel device, thereby absorbing or releasing gas into or from the liquid through the flow paths (see, for example, Patent Document 1 listed below).